Abstract: An electro-optical device, including: a substrate; an optical waveguide composed of an electro-optic material film formed in a ridge shape on the substrate; a buffer layer configured to cover the optical waveguide; and an upper electrode provided on the optical waveguide through the buffer layer, and the buffer layer has a recess on the upper electrode side above the optical waveguide. Accordingly, the propagation loss of light can be suppressed.

Abstract: The optical device includes a substrate, a waveguide layer having a slab portion that is provided in contact with the substrate and a ridge portion that is provided to protrude from the slab portion, a buffer layer that is provided so as to cover the waveguide layer and contains, as a principal component, SiO2 having a refractive index adjusted to be not less than 1.2 and less than 1.4, and a protection layer that is provided so as to cover the buffer layer and suppress a change in the refracting index of the buffer layer.

Abstract: An electro-optic device which is provided with: a substrate, an optical waveguide formed on the substrate, and an upper electrode formed on the optical waveguide. The electro-optic device is further provided with a buffer layer formed between the substrate and the upper electrode, and a boundary portion of the optical waveguide and the buffer layer forms an oxide layer different from the optical waveguide and the buffer layer in composition.

Abstract: An optical modulator, including: a substrate; a plurality of electro-optic material layers formed on the substrate; and an electrode formed on the electro-optic material layer; wherein the electro-optic material layer has a patterned RF portion waveguide that applies a modulated signal and a patterned DC portion waveguide that applies a direct current bias signal; and on a section perpendicular to a light propagation direction, the sectional area of the DC portion waveguide is greater than the sectional area of the RF portion waveguide.

Abstract: An optical device and an optical modulator, the optical device includes an optical waveguide, at an surface of plate-like or film-like electro-optic material forming the optical waveguide, 3 locations are selected in the extension direction of the optical waveguide, and 2 locations are selected in the width direction of the optical waveguide in a range of a region of 0.1×0.1 ?m, and for a total of 6 locations, an surface roughness RMS is measured with Atomic Force Microscope, and an average of the RMS is 5.1 nm or less.

Abstract: An optical device includes: a waveguide module; and a light-emitting module, in which the waveguide module includes: a base layer; a cover layer; and a waveguide layer disposed between the base layer and the cover layer, and including an optical waveguide having an incident end facet that has a curved surface and on which a laser beam to be propagated becomes incident, and the light-emitting module includes: a laser diode that emits the laser beam; and a carrier that supports the laser diode in such a manner that an emergent surface from which the laser beam emerges is positioned facing and spaced apart from the incident end facet, and that is integrated with the waveguide module by being bonded to the base layer.

Abstract: An optical modulation element is provided with a substrate, a waveguide layer formed on the substrate, a dielectric layer formed on the waveguide layer, and an electrode formed on the dielectric layer. An outer peripheral end portion of the dielectric layer has an offset area positioned inside an outer peripheral end portion of the substrate. In at least a part of the offset area, a distance from the outer peripheral end portion of the substrate to the outer peripheral end portion of the dielectric layer is equal to or less than a distance from the outer peripheral end portion of the substrate to the outer peripheral end portion of the electrode.

Abstract: The optical device includes: a substrate; a waveguide layer which is formed on the substrate and which has an optical waveguide for propagating light; a protective layer provided on the waveguide layer; and a groove which extends from the protective layer to the waveguide layer, wherein the groove includes a first side surface and a second side surface which opposes the first side surface, the first side surface and the second side surface expose end surfaces of the waveguide layer and the protective layer, and the second side surface has a rough surface.

Abstract: An optical device, including a substrate; an optical waveguide provided in a predetermined region of the substrate and formed of an electro-optic material film; a protective layer formed adjacent to the optical waveguide; and a non-light-propagation optical waveguide provided outside the predetermined region, wherein the surface roughness of the non-light-propagation optical waveguide is RMS 0.5 nm or more. According to the optical device, the occurrence of micro-cracks on the optical waveguide can be suppressed, thereby reducing the light propagation loss.

Abstract: An electro-optical device includes a substrate, an optical waveguide formed on the substrate, a buffer layer formed on the substrate which is provided so as to cover the optical waveguide and an electrode formed on the buffer layer, when viewed in a propagation direction of light, a side surface of the optical waveguide has at least one slope change point. An electro-optical device can reduce the driving voltage and the propagation loss of light.

Abstract: The optical device includes a substrate and an optical waveguide formed on the substrate, a protrusion portion is formed on the substrate adjacent to the optical waveguide. Accordingly, an optical device which can achieve further suppression of the light propagation loss and higher reliability is provided.

Abstract: An optical modulators is disclosed. The optical modulator includes a substrate, an optical waveguide formed on the substrate, a signal electrode formed on the optical waveguide via a first buffer layer and applying a modulation signal to the optical waveguide, and a bias electrode formed on the optical waveguide via a second buffer layer and applying a DC bias to the optical waveguide, the first buffer layer and the second buffer layer are formed in such a way that either one of the first buffer layer and the second buffer layer covers an end surface of the other one of the first buffer layer and the second buffer layer at a boundary part of the first buffer layer and the second buffer layer. Accordingly, an optical modulator with high reliability can be provided.

Abstract: An optical modulator includes a substrate; an electro-optical material layer formed on a predetermined region of the substrate; a buffer layer formed on the substrate which is provided so as to cover the electro-optical material layer; and an electrode formed on the buffer layer. The electro-optical material layer has a RF portion optical waveguide which is applied with a modulation signal and is patterned, and a DC portion optical waveguide which is applied with a DC voltage and is patterned. The electrode has an RF portion electrode formed on the buffer layer where the RF portion optical waveguide is located and a DC portion electrode formed on the buffer layer where the DC portion optical waveguide is located. The film thickness of the DC portion electrode is smaller than the film thickness of the RF portion electrode.

Abstract: To provide an optical modulation element whereby reduced drive voltage and suppression of DC drift can be obtained at the same time. An optical modulation element includes: a substrate; and an optical waveguide formed of an electrooptic material film formed on the substrate and having a ridge part which is a protruding portion, and a slab part having a smaller film thickness than the ridge part 11r. The optical waveguide includes a first waveguide part having a first ridge width and a first slab film thickness and to which an RF signal is applied, and a second waveguide part having a second ridge width and a second slab film thickness different from the first slab film thickness and to which a DC bias is applied.

Abstract: An optical device, including a substrate and a plurality of optical waveguide paths formed on the substrate and having slab portions with different thicknesses.

Abstract: An optical device includes: a substrate; and at least two optical waveguides formed on the substrate and facing to a multiplexed portion on the substrate in a light propagation direction, the optical waveguide includes a lamellar portion and a protruding portion which protrudes from the lamellar portion, in a cross section perpendicular to the light propagation direction, the thickness of the lamellar portion between the protruding portions of the at least two optical waveguides is greater than the thickness of the lamellar portion at the side of a side surface of the protruding portion of the optical waveguides, which does not face to other optical waveguides. Thereby, the transmission loss of light during multiplexing light can be reduced.

Abstract: An optical device includes: a substrate having a pair of main surfaces opposite each other in a first direction, end surfaces adjacent to the main surfaces, and a pair of side surfaces, and an optical waveguide, disposed along the main surface of the substrate and having a light incidence end or a light exit end in the direction of a plane where the end surface is located, wherein, an adhesive for connection is coated on the end surface of the substrate, and at least one stepped portion is formed between the optical waveguide and the adhesive.

Abstract: An optical device includes: a substrate; and at least two optical waveguides formed on the substrate and facing a multiplexed portion on the substrate in a light propagation direction, wherein in a cross section perpendicular to the light propagation direction, an angle formed between the substrate and a side surface of one optical waveguide, which faces the other optical waveguides, is set to ?, and an angle formed between the substrate and a side surface of one optical waveguide, which does not face the other optical waveguides, is set to ?, satisfying ?<?, wherein ??90°, and ??90°. Therefore, light propagating through the at least two optical waveguides tends to propagate between the optical waveguides when approaching the multiplexed portion. As a result, the light transmission loss during multiplexing light can be reduced.

Abstract: An optical device includes: a substrate having a pair of main surfaces opposite each other in a first direction and an end surface adjacent to the main surface, and an optical waveguide formed on the substrate and having a light incident surface or a light exit surface in a direction of a plane where the end surface is located, where at least a central portion of the light incident surface and/or light exit surface of the optical waveguide includes an inclined surface having a preset angle with respect to the end surface of the substrate.

Abstract: An optical waveguide element includes: an optical waveguide having a ridge part and a slab part having a thickness less than the ridge part. The optical waveguide includes: a first waveguide having a first ridge with and a first slab film thickness; a second waveguide having a second ridge width and a second slab film thickness; a first intermediate waveguide connected to the first waveguide and having a third ridge width and the first slab film thickness; and a second intermediate waveguide connected to the second waveguide and having a fourth ridge width and the second slab film thickness. The first waveguide, the first intermediate waveguide, the second intermediate waveguide, and the second waveguide are arranged in this order; the second slab film thickness is larger than the first slab film thickness; and the third ridge width is larger than the fourth ridge width.